BOV recomendations

So the new car currently doesn't have a bov, and as far as I'm aware this is putting extra strain on the turbos is it not?

Now the car sounds epic on boost and I love the noise when you let off, so looking to retain as much of this as I can. Now what BOV would be a good choice to use without adding in some good awful loud PPPPSSSSHHHH noise every time I let of the throttle. The noise currently is great and dont want to sound like some chav from the 90's.

Any help on some supra specific kits available because as you all know I'm new to the world of turbos coming from an NA?

Thanks in Advance

Hi mate, i currently have no BOV and I run a HKS intake and FMIC, it sounds great but as you mention is it safe? that is a big debate. I have a manifold intake with a HKSSSQ welded into it waiting to go on, but that is probably more the PSSSHHH sound that you dont like.. TBH i liked how it sounded with the HKS and the stock BOV in it, ill try seeing if I got a video.

I have an HKS SSQV you can burrow and see what you think. Text me if you want

Isn't there something inside the HKS Bov that can be changed so it doesn't have the ppppsssshhhh sound and instead makes it quiet.

I think the HKS racing BOV is silent so Lee P told my dad. So in theory you wouldn't notice you had one but it would still be doing its job if that makes sense?

Might suit your needs Jake?

personally i just wouldnt run one, i dont really see the need?

mine has the recirc valve blocked and no bov runs sweet as a nut

personally i just wouldnt run one, i dont really see the need?

 

mine has the recirc valve blocked and no bov runs sweet as a nut

The only thing to note when doing this is it will pressurise the system when you let off. My old intercooler blew at the welds and I'm pretty sure it was down to blocking off the recirc. I just run the stock BOV now.

Interested in this as well as my Greddy one is going in the bin. Think it's a fake as it's leaking a hell of a lot. Don't like the sound of the SSQV tbh and Im currently running without one. I convinced myself I don't need one but if a good sounding one came along and I could get it on the flange I have on the IC pipe work I'd consider it.

My Greddy one sounded great btw, more a psshhht than a whistle

I went with the ARC BOV with hardpipe, nice quality and the hardpipe is designed to fit with the stock airbox. 6 years on and never had a problem with it.

If you don't like the sound I'd just get a stock one to fit back on if your worried, even tho lots of people say they don't run a BOV and had no problems.

Stock bov or none at all

The only thing to note when doing this is it will pressurise the system when you let off. My old intercooler blew at the welds and I'm pretty sure it was down to blocking off the recirc. I just run the stock BOV now.

Well i think the rubber bung ( bottom of a walking stick) and the jubilee clip would pop off before a weld blew,

I'd but that down to age or manufacture error before over pressure in the system surely?

And i'm only running .95 boost, not like i'm running a big single at 2 bar+

Well i think the rubber bung ( bottom of a walking stick) and the jubilee clip would pop off before a weld blew,

 

I'd but that down to age or manufacture error before over pressure in the system surely?

 

And i'm only running .95 boost, not like i'm running a big single at 2 bar+

If you measured the pressure pre-throttle body you would see a huge spike when letting off without a BOV. The turbo keeps spinning, increasing the pressure, with it not having anywhere else to go. It's the one and only reason I'll be running a BOV.

As for suggestions, they all sound pretty similar. They all have the BOV whoosh noise so your only other option is to re-circ and lose the noise altogether.

If you measured the pressure pre-throttle body you would see a huge spike when letting off without a BOV. The turbo keeps spinning, increasing the pressure, with it not having anywhere else to go. It's the one and only reason I'll be running a BOV.

 

As for suggestions, they all sound pretty similar. They all have the BOV whoosh noise so your only other option is to re-circ and lose the noise altogether.

are they not fitted to stop the sound of compressor surge that to an average consumer would sound like a broken car?

personally i like the sound, and have no worry of running without one,

the pressures involved in the intake of a car are relatively low so even if it does have a pressure spike i cant see it being that great?

also does it not cause issues for facelift/uk spec supras using a maf sensor?

are they not fitted to stop the sound of compressor surge that to an average consumer would sound like a broken car?

 

personally i like the sound, and have no worry of running without one,

 

the pressures involved in the intake of a car are relatively low so even if it does have a pressure spike i cant see it being that great?

 

also does it not cause issues for facelift/uk spec supras using a maf sensor?

Stock the car runs a recirculating blow off valve. A lot of people think this is a noise suppressant and I would agree, I would also put it that it's to stop any increased pressure. A simple way to measure the spike would be to put a boost gauge in pre-TB. That would show you the peak boost if you had a peak option on the boost gauge. My guess is it would go pretty high when on both turbos at full chat and suddenly closing the throttle.

I prefer the sound of the 2JZ without a blow off valve, the turbo flutter sounds awesome. I dont know exactly what happens to all that pressure when the throttle body is closed, its not like the pipework can expand...the boost has nowhere to go except back through the turbo. If BOV's werent needed, then Mr T wouldnt have integrated it into the original design. People argue about the longevity of the turbo, but it sure as hell puts unnecessary stress through the components of the turbo system

Run without, there are a few members that don't now myself included. IIRC johnny g's upgraded twins ran without and he didn't have any problems. As a shameless plug I have a pair of Samco blanking caps should you decide you wish to try this route

E2A

One of our more wiser prominent members (i'll let you guess which one) had this to say on the subject a while ago.

There's a vast amount of rubbish talked about blow off valves. They were designed to stop customers complaining of "funny noises" on early turbo cars, they do nothing to aid spool, can be unreliable, add weight and complexity, and are now used to do the exact opposite of their original purpose. That is they are now used to make silly noises, a mechanical means of shouting "I have a big one" from under the engine cover of the car. (IMHO). To say they stop shock loadings is also incorrect. If they aided spool and added turbo reliability every turbo charged 24 hour Le Mans prototype, and every F1 engine in the turbo era would have had one. The fact is, none did.... Maybe all the drivers were supremely endowed?

 

In the F1 era turbos often didn't last a single race, so if a simple BOV would help them live longer, what do you reckon they'd have fitted?

 

Le Mans is won or lost on reliability, to a large extent. Again, a simple BOV would be fitted if it gained reliability. Honestly, a lot of the stuff on the net is garbage on this subject.

 

If I/C's are splitting and pipes blowing off it's more down to unsuitable I/C's and piping systems being used than no blow off valves, per se. If you DO choose to believe they help spool then you would certainly need a recirculating BOV achieve any hope of this. A proper intercooler designed for the higher boost pressures will not split, nor will pipework joined by proper Adel Wiggins fittings blow off.

Thanks guys for all the input and advice its much appreciated. And despite the split in opinion, I think Im decided on fitting one for piece of mind.

I think the HKS racing BOV is silent so Lee P told my dad. So in theory you wouldn't notice you had one but it would still be doing its job if that makes sense?

 

Might suit your needs Jake?

This could be a good option thanks Chris. Will fire Lee a message enquiring about it.

As for all these different BOV's if anyone is able to post audio/ video of them fitted to a TT bpu that would be great to help my decision.

I love the turbo flutter, but I love my turbos more, therefore I run a BOV

Can of worms... I've never run a bov on my big single supra or my rx7 and had no problems at all.

I ran my BPU with NO bov for a short time and had no fluttering, sounded more like a duff baileys so i put the HKS back on

If you decide to go for an HKS SSQV I have the latest version (I think it's the 4) in as new condition which I would like to sell so send me a PM. I might even still have the box.

If you decide to go for an HKS SSQV I have the latest version (I think it's the 4) in as new condition which I would like to sell so send me a PM. I might even still have the box.

Brilliant thanks mate,

Matt has very kindly sent me his to trial on mine so will see if I like it and pm you. True forum spirit You have to love this place some members are great.

No worries buddy let me know

hks bov's can be fitted in the stock location and recirc'd back into the inlet as stock to quieten it